120VAC Smokes in New Construction

[beelzerob]

Well, here's how I understand the smoke alarms to work (I think).....

The smoke alarms are wired together, whether you run your LV wire to it or not. That's code. So, they're GOING to go off together. And if you look at the wiring diagram, you'll see a red wire that is labeled tandem...that's what causes 1 smoke to cause all other smokes to go off.

However, for the low voltage connection that we'd use to trigger a signal, I believe the difference in the CC and CX is what causes that to close. In the CC, that connection won't close unless that particular smoke senses smoke. In the CX, that connection won't close unless the tandem line triggers it.

So, to me the difference is that I'll be able to see immediately which smoke alarm triggered, even though all smoke alarms are blaring. The downside is I'll have to run firewire to every smoke, and then to my Elk panel. The cheaper, easier way is to just replace one smoke with a CX, and then you'll be notified that all your smokes are going off...but you won't know which one started the racket.

I definitely wouldn't interfere with the ability of the smokes to trigger each other. The inspector checks for that, anyway....and good thing.

Anyway, that's my VERY limited understanding of what's going on. But I'm STILL trying to just find a place to buy these things....

 

[Ranger Digital]

beez, ah, yes, makes perfect sense. thanks bud!

 

[Ranger Digital]

here are the install and owners manual and a pice.

http://reliablecctv.com/sensors+%26+detect...+backup+battery

 

[beelzerob]

hey, glad I could help...and now YOU'VE helped by giving me the manual and an actual price!

Now the only remaining questions I have....what's the difference between the Form A and Form C relay? I see that one of them requires 3 wires, and the other 2. And how should i go about actually connecting to those things? Is there going to be an issue connecting low voltage wiring to something that also has high-voltage wires connected to it?

 

[beelzerob]

Well, thanks mr. Google....answered the first question, at least.

http://zone.ni.com/devzone/cda/tut/p/id/4782

 

[wired-up]

I just finished installing my GE 350 smokes and connecting with my M1G. Easy to install. Bought mine here Slightly cheaper than other link above (but check shipping costs to be certain)
As for mixing High and low voltage, check with your electrician and inspector. One of the benefits (and Hazards) of living in the backwoods of Alabama is that there is no inspection. (Somewhat frighting as we close on our new home next week)
I ran a dual gang box with a divider and sheetrocked over the low voltage side so the detector would cover the opening.
David

 

[beelzerob]

Oh, thanks for the link! I wonder if these places do discounts for bulk orders (if over a dozen is bulk...)

Now that I look at them, I realize that the 320 does the same things as the 350, but I guess uses a photo electric sensor instead of something else. Have to decide if my house and family are worth $7 more per detector......

how did you actually hook them to the Elk? did you just use 2 conductor wire, and if so, how were they connected to the detector?

I've decided that what I'll do is use all ACC models, except for 1, which will be ACX. That way, there's a little redundancy. If I use all ACC models, which only close the relay if they detect the smoke, then that leaves me vulnerable to not detecting a problem, should the wire or detector fail somehow, because I won't be able to detect the tandem alarms going off. but, if I use just one ACX, then it'll go off if any other alarm does...and i can still use it to determine the alarm location, because it'll be the only one sending a signal to the elk, which means it had to have been the original detector.

 

[wired-up]

I used 2 conductor wire. There is a connector with flying leads (loose wires) of the colors listed in the manual linked above. You can use any zone as an input on the elk and identify it as a fire zone.
I just went with one relay model, rest tandem. I figured if they go off I won't waste time looking at the keypad to see which one is alarming, just follow our fire escape plan. If you have the wire and the zones available though, it can't hurt to be redundant.
David

 

[beelzerob]

I just went with one relay model, rest tandem. I figured if they go off I won't waste time looking at the keypad to see which one is alarming, just follow our fire escape plan. If you have the wire and the zones available though, it can't hurt to be redundant.
David

Ok, simple bare wire connections...good!

Heh...ya, I try not to tell too many people about wanting to see where the fire is because then they think I'm going to run to the computer when the firealarm goes off, instead of saving our kids. Obviously fighting a fire comes after getting everyone safe. But our house is 2-story with a basement, and kinda big....so it'd be nice to be able to glance at a mounted touchpad and see where the offender is, maybe have a chance at stopping it before it gets outta hand. We're very rural, so its either fight it, or expect a total loss.

The nice thing with CQC is, as soon as it detects which one went off, it can automatically wake up all the touchpads in the house and change the display to show where it is, so all I'll have to do is glance at it while on my way to get everyone, I won't have to press a single button.

 

[bmil]

I think the difference in the 320's and 350's was the 350's have the 9v battery back-up (if my poor memory is working).

* I'm not sure if the 350's will work with another brand of smoke on the tandem line (is there a standard or does each manufacturer do their own thing?) In my set up I used all 350's tied in tandem, 6 no relays, 1 relay. You might want to verify before mixing brands on the tandem line.

 

[beelzerob]

Ok, thanks. 9V backup is definitely a requirement. I won't be mixing brands, they'll all be 350's. Just all CC's except 1 CX.

 

[me2]

* I'm not sure if the 350's will work with another brand of smoke on the tandem line (is there a standard or does each manufacturer do their own thing?)

I would like to know the answer to that too.

 

[Ranger Digital]

me2, me too!

 

[Mr.Tim]

Each manufacturer does their own thing.

Smoke detectors should come with a compatibility matrix that tells you what they will work with.

Also, many manufacturers make 120v/bb smokes with form c relays (gentex is another).

most muni's make it difficult to use anything but the 120v/bb. If you know the ins/outs you can use a low voltage system instead.

The important facts are:
-you need a smoke alarm, not a smoke detector (you need a sounder in each detector)
-you need primary power furnished from the building wiring
-you need battery power when the primary power is gone

Does something like an elk m1 receive power from the building?

Does the elk m1 furnish battery power in the event of power outage?

Keep in mind that wireless smokes are approved for use in commercial spaces.. I agree that the reason they are hardwired is to eliminate the idiot-factor. If you don't maintain your panel, you'll lose all your fire protection. However, I don't see where the code prohibits a low voltage system. The inspector may prohibit it, but you would win on appeal.

I also think the new NFPA 72 (national fire alarm code) has made significant changes in this area.
Good luck,
Tim

 

[Sacedog]

Ok, thanks. 9V backup is definitely a requirement. I won't be mixing brands, they'll all be 350's. Just all CC's except 1 CX.

Why wouldn't you just install all CCs? If any of the CCs go off, the Elk panel will know. I suppose that if the CC that is going off had a wiring failure, and didn't notify the Elk, the CX would catch it; but I can't think of any other benefit. Besides, if your smokes are going all, they will all be sounding in alarm state...you are gonna know.